At a previous employer, we purchased a "commercial" hipot tester. I
don't recall the manufacturer, but I believe it was Rod-L or
Hipotronics. It was essentially a low current DC supply. You could
twist a knob to set the DC voltage to anywhere up to 20kV, and you could
set a current trip point up to 20mA. It was quite inexpensive, maybe
$500 for a single quantity.
What is interesting is what they used for an HV connector, cable and
probe. The "power supply" end of this cable used a modified SO-239, and
the "probe" end used a modified PL-259, similar to what has been
described on this reflector in the past few days. The inner parts of
both the plug and jack were hollowed out. The cable had the braid
terminating, therefore, on the shell of the PL-259, and then perhaps
four inches of solid (not foam) dieletric protruded, after which the
center conductor was soldered to a male banana plug. Inside this HV DC
power supply was a plastic (polycarbonate) tube just slighly larger than
the solid poly dielectric of the RG-8 that was the probe cable, and at
the end of this tube was a female banana jack. The ground and center
conductor mated pretty much at the same time, which bothered me, but not
UL, since this whole rig carried a UL approval tag.
The "probe" was about six feet of RG-8 with a solid polyethylene
dielectric. The active end folded the braid back for an inch or
thereabouts and had a stranded wire soldered to it, a few feet long,
terminated in alligator clips. The center conductor continued for a few
inches, terminated in nothing more than simply being stripped and tinned
at the end. In our usage, we used short alligator clip leads from the
end of the RG-8 to whatever we were testing..as short as possible. The
sorts of things we were testing were vacuum variable caps, tubes, etc.
A common test we'd do is to set the DC HV to 10kV or more and leave it
on overnight. In the morning, we'd see if the overcurrent had tripped,
and we normally set the overcurrent to 1mA or less.
And all that in a UL-approved device!
Regards W8NF
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